1. Field of the Invention
This invention relates to a communication apparatus used upon being connected to an ISDN, by way of example. The invention further relates to a communication method using this communication apparatus.
2. Description of the Prior Art
In general, a facsimile apparatus connected to an ISDN is capable of sending and receiving facsimile documents in G3 and G4 modes. An apparatus has also been proposed in which two 64 Kbit/s B channels are used to enable facsimile transmission and reception in the G3 and G4 modes simultaneously in order that a plurality of the B channels of an ISDN can be exploited effectively. When a facsimile apparatus of this kind is used, the plurality of communication channels of the ISDN are employed without distinguishing between facsimile transmission and facsimile reception.
Consequently, in the example of the prior art described above, when a facsimile transmission is being carried out using one B channel, facsimile reception using one other B channel is possible, and therefore a situation can arise in which the two B channels are used for facsimile transmission and reception simultaneously. In such case, transmission/reception of another facsimile signal through this communication line becomes impossible, and a conversation by telephone through this ISDN also can no longer be carried out.